The geometric and electronic structure of oxygen on a Re(10[formula omitted]0) surface investigated by LEED and ARUPS

Abstract

The geometric and electronic structure of oxygen dissociatively adsorbed on a Re(1010) surface has been studied by means of LEED and ARUPS. Five ordered oxygen LEED phases could be observed, namely, a (2×3)-O structure at θO = 16, a c(2×4)−20 structure at θO = 14, a (1×5)−20 structure at θO = 25, a (1×4)−20 structure at θO = 12, and a (1×3)−20 structure at θO = 23. The two dimensional band structures of the (1×5)−20 and the (1×3)−20 phase were mapped at BESSY. Both ordered oxygen overlayers showed quite similar band structures with a pronounced dispersion along Σ ([1210]-direction) but a lack of any dispersion along Δ ([0001]-direction). The oxygen-induced bands could be assigned to certain symmetric and antisymmetric states of two chemisorbed oxygen atoms per unit cell by considering dipole selection rules in combination with final state symmetries. The uniform behaviour of both band structures can be interpreted by a similar local arrangement of the oxygen atoms in the unit cells of both structures.